Indeed, there is nothing more repulsive than these monsters that defy nature and are known by the name of witcher, as they are the offspring of foul sorcery and witchcraft. They are unscrupulous scoundrels without conscience and virtue, veritable creatures from hell capable only of taking lives...

A witcher (also wiccan or hexer) is someone who has undergone extensive training, ruthless mental and physical conditioning, and mysterious rituals (which take place at "witcher schools" such as Kaer Morhen) in preparation for becoming an itinerant monsterslayer for hire. Geralt, the central character in Andrzej Sapkowski's Witcher series and the subsequent games inspired by them, is said in the stories to be one of the greatest witchers; he is certainly legendary, but whether famous or infamous is more open to interpretation (and/or subject to gameplay, as the case may be).

Taken in as children, witchers-to-be are subjected to intense alchemical processes, consumption of mutagenic compounds, and relentless physical and magical training to make them dangerous and highly versatile against their vast array of opponents, many of which possess superhuman speed, strength and/or other deadly powers. These procedures ultimately mean that each fully-trained witcher is a mutant built specifically to hunt and kill inhuman prey. The key permanent results of mutations shared by all witchers include:

Sterility (which partially explains selection from the outsiders, as they cannot breed to pass on their traits).

Cat-like eyes that grant very acute nightvision - witchers can constrict their pupils to see in blinding light or open them to see in near pitch darkness. This nightvision can be further enhanced with the cat potion, but in general, it is good enough by itself to not require further enhancement.

Tremendous resistance to disease (which functions in most cases as complete immunity) and a boosted immune system, allowing them to consume large quantities of potions that could prove easily deadly if consumed even in small amounts by a normal man.

Exceptionally increased strength, speed, reflexes, and endurance, far beyond any normal or well-trained human, that allows them to swiftly end fights with minimal effort, and perform physical feats non-witchers couldn't hope to match. A witcher's physical skills alone are sufficient to defeat most monsters single-handedly if combined with extensive training and proper weaponry, whereas regular men could only hope to accomplish this in large groups. Witchers have also been shown to shrug off hits that would normally render normal men unconscious. Additionally, they have been known to survive the strikes of powerful monsters such as giants, or other beings possessing heruculean strength, that would otherwise kill others with a single blow.

Having the ability to perform simple yet incredibly versatile combat magic in the form of signs. They also develop a sixth sense that allows them to "feel" things around them, be it items of importance or people's immediate intentions. This explains their uncanny ability to track and hunt people and monsters.

Accelerated healing granting quick recovery from injuries.

Incredibly long lifespan and prolonged youth (Vesemir is said to be at least a few centuries old but has the appearance of a middle-aged man).

Though they cover proficiency in basically any weapon that comes to hand, a witcher's training focuses on two primary tools:

These swords are typically carried on the back. A steel blade used for more mundane beings, while a silver blade for beasts of the supernatural. Witchers are also frequent mixers and users of powerful potions, having developed an advanced tolerance to their inherent toxicity, but still limited to a few at a time (even one of their weaker brews would be fatal to an ordinary human). Finally, their formal magical training deals with signs, a low-level yet versatile form of magic that allows witchers to cast spells and enchantments with simple hand gestures. Without extensive improvement and practice, these are mere tricks compared to what a sorceress can do, but they serve very well for someone with a sword in one hand to add a variety of improvisation to their efforts. Also, the more powerful magic used by mages often takes a lot of time to prepare while all signs are instantaneous. Additionally, witchers are trained by seasoned mages in how to use these signs to the best effect.

In general, a witcher is a formidable and often overwhelming opponent to more mundane races thanks to their superhuman physical prowess, regenerative capabilities, and magic. However, they are not infallible, as they can still make mistakes, take a misstep in battle against mundane men or supernatural demons, or be overwhelmed by sheer numbers and individuals who have the skill to match a witcher, though rare is the individual who managed to slay a witcher out of skill rather than dumb luck or by ambush.

Though a witcher's eyes are one way to stick out, another standard means of identification is the witcher medallion. This device aids in the detection of monsters, and no witcher would part with one willingly. (And of course, witchers are known for being 'hard to kill' - Leo Bonhart boasts a collection of three such medallions as proof of his martial skill.) The form of an individual medallion (head of a wolf, cat, griffin, etc.) indicates the school at which its owner was trained.

It is a common belief, even among witchers themselves, that they have no capacity for emotion. This may be debatable, and rather relative, considering the rigors of their training and the dangers they face on a day-to-day basis. Perhaps they have simply never had the time or exposure to society to develop or recognize the reactions to mundane experiences that most take for granted. It may also be explained that a combination of their hard training, genetic modifications, and seclusion from society that may encourage blunted emotional expressions, as Geralt, Lambert, and Eskel all exhibit emotional heights concerning love, joy, fear, anger, lust, and sympathy among various others.

Occasional references to witchers as 'nonhuman' are somewhat at odds with the original stories (in which Geralt only identifies witcher as a profession, never a race). There is certainly no official classification as such, and the relevant references (in the first game at least) are usually from Geralt identifying with the mistrust and/or hostility faced by elves and dwarves in human society. Likely it is used as a slur against the mutants, likening them to elves and dwarves, though it's worth noting that an in-game text found in Wild Hunt mentions that the Cat School of witchers "are for the most part of elven stock," indicating that there are (or were at one time) indeed nonhuman witchers. Whether or not there actually are any elven witchers during the contemporary timeline of the story is unknown.

Witchers came into being when the first settlers were colonizing the untamed lands of present-day Temeria. The elite caste of warrior-monks was to defend humans from the monsters which inhabited the wild. Thanks to mutagenic mushrooms, herbs, and plant stimulants, the bodies of young apprentices developed superhuman speed and endurance. As a result of the painful and dangerous Trial of the Grasses, young witchers gained cat-like eyes, which allowed them to see in the dark. With the help of sorcerers, they learned to utilize simple combat spells, called signs, as well as magic potions that augmented their fighting skills. Nowadays, when monsters have become something of a rarity, the demand for the witchers' services has declined significantly. Only a few representatives of the caste still travel the world, and no more monster slayers are being made.

Due to their otherness, unusual abilities, and magicals skills, witchers are treated as outcasts and sometimes even met with hatred. This hatred was made manifest during the infamous attack on Kaer Morhen, which led to the destruction of the fortress and the death of most of the witchers wintering there. Those who survived are doomed to extinction since they no longer train successors.

People need witchers, but are simultaneously afraid of them. The itinerant warriors inspire fear because they are mutants and have superhuman powers. A witcher is rarely a welcome guest and contacts with members of this profession are almost always limited to business. Witchers are invariably attacked during pogroms and social upheavals directed against those who deal in magic.

Mutagens and magic render witchers' bodies resistant to all kinds of disease, even to the point of outright immunity.

Despite my long friendship with Geralt, I know little more about this peculiar brotherhood or guild than learned tomes provide. On top of that, I am obliged to discretion, so I shall write nothing more than necessary on the subject. Once as numerous as the beasts they fought, today the witchers are seen as a relic of times long gone. The exact character of their training remains a mystery. It is known it consists, among others, of the Trials - processes that transform the organism using a specific combination of secret herbs and infusions. Those who survive them gain superhuman reflexes, speed of reaction, the ability to see in the dark and many other traits making them lethal foes. During their training they learn swordplay and basic magic, known as signs. Armed with this set of abilities, the witchers can effectively fulfill their objective, that is protecting humans from the monsters inhabiting our world.

The original Polish name for "witcher" is "wiedźmin". The English translation preferred by Andrzej Sapkowski was initially called a "hexer" and is the name used in the international version of the film adaptation. However, CD Projekt chose to translate it to "witcher" in the computer game, and this word was subsequently adopted by Danusia Stok (in her translation of The Last Wish) and even by Sapkowski himself (in Historia i fantastyka).

Warlock has been used in informal English translations, although "witcher" - being a neologism in English - is arguably better at capturing the spirit of Geralt's and a witcher's profession.

Only human witchers are known to exist, although it is believed that elven witchers may exist or have existed in the Cat school.

In old Slavic folklore wiedźmin (however, female wiedźma was more common in most places) was a person who had an extensive knowledge in the matters of herbs, medicine, healing and tribal "magic". Wiedźmy (the witches) and wiedźmini (the witchers) usually acted in their local communities as healers and counselors and were respected by the people. They were often associated with Slavic god Veles, the horned god of the Underworld, night, magic and knowledge (but also cattle, trade and craftsmanship). The very word wiedźma and wiedźmin means "the one who knows" and is etymologically related to the words like wiedza - "knowledge" and wiedzieć - "to know". After the Christianization, due to their exclusively pagan connotations, wiedźmy and wiedźmini were demonized as evil beings and servants of Satan.